The present invention relates to a cartridge including an anti-ram device.
In prior single-control lever faucets, the faucet flow-rate control devices conventionally comprise ceramics screw elements or single-control lever mixing cartridges which have a comparatively short driving stroke providing, in a regular use condition, a very quick closure of the faucet.
This feature is self-evident in the so-called “quick pitch” faucets, which, however, just because of their quick type of operation, and due to middle-high pressures in the water distributing system, are frequently subjected to an undesired phenomenon, the so-called ram-surge, generated in the water pipes and substantially consisting of a return pressure wave generated by an abrupt interruption of the water flow as the faucet is closed, and tending to reverse the water flow direction.
High water flow-rates and pressures can cause the ram-phenomenon as a faucet is quickly closed.
Since the water parameters are fixed features, it is possible, for overcoming the ram phenomenon, to only affect the faucet closure speed.
Among several attempts designed for overcoming the above ram problem in single control lever faucet cartridges, the most efficient is that of using a hydraulic piston, designed for sucking water as the faucet cartridge is opened and ejecting the sucked water during the faucet closure, thereby the faucet operator is compelled to slowdown the faucet movement to fit the designed preset faucet opening rate.
In this approach, a piston draws water from an inner cavity of the cartridge, to which are conveyed hot and cold water from the faucet inlets, during the opening movement, while ejecting said hot and cold water into the cartridge cavity during the faucet closure operation.
Even if the above mentioned approach, in use for several years, operates better than other prior methods, it is however affected by three main drawbacks.
At first, for providing a given resistance, the piston must have a very large cross-section and, accordingly, a correspondingly large size.
Moreover, because of its geometrical construction, the great length of the piston may cause disalignments and inclinations of the piston control rod which must be precisely mounted on the faucet middle-line.
The second drawback is that a comparatively high counter-force is generated in closing the faucet, which force is applied at a single point and on small surfaces.
The third drawback is that, because of wear and inevitable polluting materials, the faucet operating mechanism could abruptly stop to properly operate.